Portable terminal and method of setting and releasing use restriction therefor

ABSTRACT

A portable terminal with a body having a front surface with a display device and a rear surface including a rear password input device provided on the rear surface of the body, which is opposite to the display device, to receive a setting password for setting or releasing of use restriction, a storage device that stores the input password for the setting of the use restriction, and a control device that determines the releasing of the use restriction by comparing N the password for the releasing of the use restriction, which is input into the rear password input device, with the stored password for the setting of the use restriction. The input of the password for the setting or the releasing of the use restriction is prevented from being exposed to other persons, so that the security of the portable terminal is remarkably improved.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/326,352, filed Jan. 13, 2017, which is a National Phaseapplication under 35 U.S.C. §371 of International Application No.PCT/KR2015/007677, with an International Filing Date of Jul. 23, 2015,which claims the benefit of Korean Patent Applications No.10-2014-0122271, filed on Sep. 15, 2014, at the Korean IntellectualProperty Office, the disclosures of which are incorporated by referenceherein in their entirety.

BACKGROUND 1. Technical Field

The present invention relates to a portable terminal and a method ofsetting and releasing the use restriction thereof, and more particularlyto a portable terminal having enhanced security to prevent a passwordfrom being exposed to a person around a user by setting and releasingthe use restriction through a rear password input unit provided on arear surface of a body and a method of setting and releasing the userestriction thereof.

2. Background Art

As mobile communication services have been rapidly developed, and usersusing the mobile communication services have been exponentiallyincreased, portable terminals have been provided with various functions.For example, the portable terminals have been realized in the form ofmulti-media devices having multiple functions, such as a video telephonyas well as a basic voice call, wireless Internet access, electronicpayment, a digital camera function to photograph a still image or amoving picture, MP3 and PMP functions to reproduce music or movingpictures, and a DMB function to receive broadcasting.

Accordingly, the portable terminal has various pieces of informationincluding a still image, a moving picture, a text file, or a textmessage related to the privacy of a user, which should not be exposed toother persons. Further, the portable terminal has personal informationsuch as an ID, a password, and a certificate for electronic payment.

Accordingly, recently, in a portable terminal such as a smart phone,security for the identify theft prevention and privacy protection forvarious pieces of personal information stored in the portable terminalis significantly important. As one manner to enhance the security forthe portable terminal, a use restriction function by screen locking isused.

If the use restriction function by the screen locking is set in theportable terminal as described above, even if a user loses the portableterminal or is away from a place while leaving the portable terminal,since others cannot activate functions of the portable terminal due tothe set use restriction or see the information stored in the portableterminal, various pieces of personal information or important documentsstored in the portable terminal can be safely protected.

Representative setting and releasing manners of the use restriction fora portable terminal according to the related art will be describedbelow.

First, a user sets a password by inputting a plurality of secretenumbers through a number inputting display part. Only when numbersmatching with the setting password are input, the use of the portableterminal is allowed by releasing the use restriction. The password isgenerally related to the specific information of the user, such as thebirthday, or the phone number of the user, so that others may easilyfind the password. In addition, the password is usually matched to apassword of a bank account, a password for the entrance of a door, or alog-in password for the Internet. Accordingly, when the password leakageoccurs, secondary damages may be caused.

Thus, as shown in FIG. 33, a method is mainly used that a portableterminal is enabled to be usable by releasing the use restriction onlywhen a user sets a password by inputting a shape pattern according to amoving locus through a pattern input display part, and a shape patternmatched to the set password is input.

However, in all methods of setting and releasing the use restrictionaccording to the related art, since a password is input through a touchscreen provided on the front surface of a main body of a portableterminal, when the user inputs a password or a shape pattern to releasethe use restriction, the input screen and an inputting behavior of theuser cannot help being exposed to others so that security may bevulnerable.

Especially, even when a portable terminal is not used for a while, theportable terminal is immediately in a use restriction mode according toa power saving mode, so that a user should frequently input a passwordto release the use restriction, Thus, whenever that the user inputs apassword into the front touch screen while seeing the front touchscreen, others may peep into the input screen and the inputting behaviorof the user, so that there may be a great danger to expose the passwordfor usage restriction to others.

Further, since the security is vulnerable, the user should carefullyinput passwords such as secret numbers or shape patterns or frequentlychange passwords while paying attention to whether others peep at thepasswords when the user inputs the passwords with the concerns about theleakage of the passwords, and when the user frequently changespasswords, he or she may remember the changed new password, making itpossible to use the portable terminal.

Meanwhile, in order to solve the danger of leakage of a password, amethod of providing the portable terminal provided with a fingerprintrecognition section to set or release us restrictions throughrecognition of a fingerprint has been suggested.

However, since a fingerprint of the user itself is encrypted in thesetting/releasing method through the recognition of a fingerprint, themethod has an excellent security having no concern about leakage of apassword in the everyday life, but in a specific situation, for example,when the user is not clearly conscious, for example, when the user istotally drunken or slept deep or when the user is under pressure, theuse restriction for the portable terminal is immediately released aslong as the others bring a finger of the user into contact with thefinger recognition section stealthily or compulsorily, the method ismore vulnerable than the setting/releasing method through secret numbersor pattern passwords.

SUMMARY

The present invention is made in order to solve the problem occurring inthe related art, and an object of the present invention is to provide aportable terminal having enhanced security by preventing a passwordinput for the setting and the releasing of use restriction from beingexposed to others around a user and a method of setting and releasingthe use restriction thereof.

In order to accomplish the above object, there is provided a portableterminal with a body having a front surface with a display unit and arear surface including a rear password input unit provided on the rearsurface of the body, which is opposite to the display unit, to receive apassword for setting or releasing of use restriction, a storage unitthat stores the input password for the setting of the use restriction,and a control unit that determines the releasing of the use restrictionby comparing the password for the releasing of the use restriction,which is input into the rear password input unit, with the storedpassword for the setting of the use restriction.

In order to accomplish the above object, there is provided a method ofsetting and releasing use restriction for a portable terminal. Themethod includes setting the use restriction for the portable terminalincluding a display unit provided on a front surface of a body thereofand a rear password input unit provided on a rear surface of the body,and releasing the use restriction set for the portable terminal. Thesetting of the use restriction includes inputting a password for thesetting of the use restriction into the rear password input unit; andstoring the input setting password. The releasing of the use restrictionincludes inputting a password for the releasing of the use restrictioninto the rear password input unit; and determining the releasing of theuse restriction by comparing the input releasing password with thesetting password stored in the setting of the use restriction.

As described above, according to the present invention, since thepassword for the setting and the releasing the use restriction is inputthrough a rear password input unit provided on the rear surface of thebody of the portable terminal, both of the rear password input unit,which is an input section, and the action of inputting the password bythe user are hidden by the body and not exposed to others. Accordingly,the security for the password can be remarkably improved.

In addition, the user can conveniently select and use a section or adirection of inputting a password under various use environments, andset or release the use restriction without errors.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a block diagram illustrating a portable terminal according toa first embodiment;

FIG. 2 is a block diagram illustrating a control unit according to thefirst embodiment;

FIG. 3 is a view illustrating a front surface of a portable terminalaccording to the present invention;

FIG. 4 is a view illustrating a rear surface of a portable terminalaccording to the present invention;

FIGS. 5 and 6 are views illustrating an action of inputting a passwordinto the portable terminal according to the present invention;

FIGS. 7A and 7B illustrate the inputting of a password set in a specificshape and the views illustrating the front surface and the rear surface,respectively;

FIG. 8 is a view illustrating the inputting of the password to be set ina directional pattern onto the rear surface;

FIG. 9 is a view illustrating the inputting of the password to be set ina sequential pattern onto the rear surface;

FIG. 10 is a view illustrating the inputting of the password to be setin a signal pattern onto the rear surface;

FIG. 11 is a flowchart illustrating the steps of setting use restrictionaccording to the first embodiment;

FIG. 12 is a flowchart illustrating the steps of releasing the userestriction according to the first embodiment;

FIG. 13 is a flowchart illustrating the steps of determining thereleasing of the use restriction by determining an input state whenreleasing the use restriction;

FIG. 14 is a block diagram illustrating a portable terminal according toa second embodiment;

FIG. 15 is a block diagrams illustrating a control unit according to thesecond embodiment;

FIG. 16 is a flowchart illustrating the steps of setting the userestriction according to the second embodiment;

FIG. 17 is a flowchart illustrating the steps of releasing the userestriction according to the second embodiment;

FIG. 18 is a block diagrams illustrating a control unit according to athird embodiment;

FIG. 19 is a flowchart illustrating the steps of setting the userestriction according to the third embodiment;

FIG. 20 is a flowchart illustrating the steps of releasing the userestriction according to the third embodiment;

FIG. 21 is a block diagrams illustrating a control unit according to afourth embodiment;

FIG. 22 is a flowchart illustrating the steps of setting the userestriction according to the fourth embodiment;

FIG. 23 is a flowchart illustrating the steps of releasing the userestriction according to the fourth embodiment;

FIG. 24 is a block diagrams illustrating a control unit according to afifth embodiment;

FIG. 25 is a flowchart illustrating the steps of setting the userestriction according to the fifth embodiment;

FIG. 26 is a flowchart illustrating the steps of releasing the userestriction according to the fifth embodiment;

FIG. 27 is a block diagrams illustrating a control unit according to asixth embodiment;

FIG. 28 is a flowchart illustrating the steps of setting the userestriction according to the sixth embodiment;

FIG. 29 is a flowchart illustrating the steps of releasing the userestriction according to the sixth embodiment;

FIG. 30 is a block diagrams illustrating a control unit according to aseventh embodiment;

FIG. 31 is a flowchart illustrating the steps of setting the userestriction according to the seventh embodiment;

FIG. 32 is a flowchart illustrating the steps of releasing the userestriction according to the seventh embodiment; and

FIG. 33 is a view illustrating a method of setting and releasing the userestriction for a typical portable terminal according to the relatedart.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present invention will bedescribed in detail with reference to accompanying drawings.

However, in the following description of the embodiments, if detaileddescription about well-known functions or configurations are obvious tothose skilled in the art and considered to unnecessarily make thetechnical features of the present invention unclear, the detaileddescription will be omitted.

Portable terminals according to the present invention may includevarious electronic devices, such as a cellular phone, a smart phone, atablet PC, a PDA, and a PMP, which can be carried by a user for the usethereof, without the limitations. Hereinafter, the smart phone will bedescribed as one example of the portable terminal for the convenience ofexplanation.

FIG. 1 is a block diagram illustrating a portable terminal according toa first embodiment of the present invention. The portable terminalaccording to the first embodiment includes a display unit 10, a rearpassword input unit 20, a user input unit 30, a storage unit 40, and acontrol unit 50.

Naturally, only components related to the features of the presentinvention are illustrated, and various components, such as a wirelesscommunication unit, a power supply unit, a photographing section, or avoice inputting/outputting section, may be included herein for therealization of various functions for the portable terminal if necessary.However, since the above components are well-known in the art to whichthe present invention pertains and are not related to the features ofthe present invention, the details thereof will be omitted in order toavoid redundancy. Accordingly, only the components related to thefeatures of the present invention will be described in detail below.

The display unit 10 may display various kinds of visible information,and the visible information may be displayed in various shapes includingletters, numbers, symbols, graphics, or icons.

The display unit 10 may be realized using various liquid crystaldisplays such as a plasma display panel (PDP), a liquid crystal display(LCD), a light emitting diode (LED), an organic light emitting diode(OLED), or a flexible display. In addition, the display unit 10 includesa touch screen including a touch panel to function as a touch-basedinput section as well as an image outputting section.

FIG. 3 is a view illustrating a front surface of a portable terminalaccording to the present invention. As illustrated in FIG. 3, thedisplay unit 10 is provided on the front surface of a body 1 like thatof a typical portable terminal according to the related art.

Accordingly, as illustrated in FIGS. 5 and 6, a user grips the portableterminal with the front surface facing up to view the display unit 10.In this state, the user touches various functional menus displayed onthe display unit 10 for inputting to activate and use various functionsof the portable terminal.

Although a password for setting and releasing of use restriction isinput through a screen image displayed on the display unit 10 providedon the front surface of the body 1 in a typical portable terminalaccording to the related art, the present invention has a basicdifference from the related art in that the password for setting andreleasing of the use restriction is input through the rear passwordinput unit 20 according to the present invention.

FIG. 4 is a view illustrating a rear surface of the portable terminalaccording to the present invention. The rear password input unit 20performs a function of inputting the password for the setting and thereleasing of the use restriction for the portable terminal. Asillustrated in FIG. 4, the rear password input unit 20 is provided at anopposite side to the display unit 10, that is, on the rear surface ofthe body 1 of the portable terminal.

Accordingly, as illustrated in FIGS. 5 and 6, the user grips theportable terminal with the front surface of the body 1 facing up whileinputting the password for the setting and the releasing of the userestriction through the rear password input unit 20 provided on the rearsurface.

The rear password input unit 20 may be realized using various sectionsaccording to the embodiments, and the password for the use restrictionmay be set variously depending on the realization sections.

First, the rear password input unit 20 may be realized using a touchsensor that allows the user to input the password by touching the rearpassword input unit 20 with a finger of the user, and the password forthe setting of the use restriction may have a specific shape.

In this case, as the user touches the rear password input unit 20realized using the touch sensor with the finger of the user, thespecific shape may be expressed, or memorized in at least one of shapessuch as a letter, a number, a symbol, a figure, and a graphic.

For example, as illustrated in FIG. 7A, if the user touches the rearpassword input unit 20 to express a letter of “G”, the letter of “G”becomes the set password. When a G-shaped pattern matched to the setpassword is input, the use restriction is released.

In addition, the rear password input unit 20 may be realized using adirection input section allowing the user to input directionality bydragging the finger of the user. The direction input section may includea track point or a joy stick.

When the rear password input unit 20 is realized using the directioninput section, the password for the setting of the use restriction maybe a directional pattern created as the direction input section isdragged in various directions at least one time.

For example, FIG. 8 illustrates one example of the password created asthe direction pattern. As illustrated in FIG. 8, the user sequentiallydrags the finger of the user in directions of →, ←, ∇, and ↓ on the rearpassword input unit 20 to set the password having the directionalpattern. When releasing the setting of the password, the user inputs thepassword matched to the set directional pattern for the releasing of theuse restriction.

In addition, the rear password input unit 20 may be realized using atouch sensor divided into a plurality of touch regions. Multiple touchregions may be formed, that is, two touch regions may be formed bydividing the touch sensor into the top and the bottom or the left andright, or nine touch regions may be formed by dividing the touch sensorin a 3×3 matrix. FIG. 9 illustrates fourth touch regions formed bydividing the touch sensor into the top, the bottom, the left, and theright.

In addition, when the rear password input unit 20 is realized in such amanner, the password for the setting of the use restriction may be asequential pattern created as the multiple touch regions are selectivelytouched at least one time.

For example, FIG. 9 illustrates one example of the password created asthe sequential pattern. As illustrated in FIG. 9, the user sequentiallytouches a left upper portion, the left upper portion, a left lowerportion, and a right upper portion among the four touch regions of therear password input unit 20 to set the password of the sequentialpattern. When releasing the setting of the use restriction, the usertouches the corresponding touch regions in the same pattern as the setsequential pattern to input the password and thus releases the userestriction.

In addition, the rear password input unit 20 may be realized using atouch sensor or a push button. In this case, a password for the settingof the use restriction may be a signal pattern created based on thefrequency that the touch sensor or the push button is pressed and theinterval between the pressing operations of the touch sensor or the pushbutton.

In this case, the signal pattern is a password created similarly to aMorse code by distinguishing between the frequency that the user touchesthe touch sensor or presses the push button in a row and the frequencythat the user presses the push button at a predetermined interval.

In other words, FIG. 10 illustrates a signal pattern created by pressingthe rear password input unit 20 three times in a row, pressing the rearpassword input unit 20 two times after a predetermined period of time,and then pressing the rear password input unit 20 one time finally. Thepassword having the signal pattern may be set as described above. Whenreleasing the setting of the use restriction, the user inputs thepassword by pressing the rear password input unit 20 in the same patternas the set signal pattern to release the use restriction.

In addition, the rear password input unit 20 may be a motion sensor tosense the motion of the finger of the user. In this case, the passwordfor the setting of the use restriction may be a motion pattern by thefinger of the user sensed by the motion sensor.

In other words, if a user moves the finger of the user in front of themotion sensor while forming a specific motion pattern, the motionpattern of the finger is sensed by the motion sensor and set as apassword. When releasing the setting of the use restriction, the usermoves the finger in the same motion pattern as the setting motionpattern to release the use restriction.

In the case of a portable terminal provided on the rear surface of abody thereof with a camera, the motion sensor may be installedintegrally with the camera. The motion sensor may employ various typesof sensors, such as a transmission type-photoelectric sensor, a directreflective photoelectric sensor, a mirror reflective photoelectricsensor, a high-frequency oscillation type-proximity sensor, a capacitiveproximity sensor, a magnetic proximity sensor, and an infrared proximitysensor, which are well known to those skilled in the art.

As described above, the rear password input unit 20 is realized usingvarious sections to receive passwords set in various patterns. Even ifthe rear password input unit 20 is realized using any section, the rearpassword input unit 20 is provided on the rear surface of the body 1 ofthe portable terminal. Accordingly, when the user grips the portableterminal normally as illustrated in FIGS. 5 and 6 (that is, in themanner of facing up the display unit 10 provided on the front surface ofthe portable terminal) and inputs the password through the rear passwordinput unit 20, both of a password inputting action, such as a touchingaction or a dragging action, of the user and the rear password inputunit 20 are naturally hidden by the body 1 of the portable terminal,thereby effectively preventing the information of the input passwordfrom being exposed to others around the user.

The user input unit 30 may include variously-shaped input buttons thatallow the user to input instructions through the operation thereof, andmay be provided on the front surface or the lateral side of the body 1of the portable terminal.

The user input unit 30 receives instructions to control variousoperations, such as starting, terminating, scrolling, and controlling ofa sound volume, of the portable terminal and sends the instructions tothe control unit 50. Particularly, the user input unit 30 may receiveinstructions for the setting and the releasing of the use restrictionand send the instructions to the control unit 50.

The storage unit 40 may be realized using at least one of storage mediasuch as a flash memory type, a hard disk type, or a multi-media cardmicro-type of a memory, a card type memory (SD or XD memory), a RAM, aROM, an EEPROM, a PROM, a magnetic memory, a magnetic disk, and anoptical disk.

The storage unit 40 stores various pieces of information required forthe operations of the portable terminal or generated during theoperation of the portable terminal. In other words, the storage unit 40may store programs for processing and control operations of varioussignals, which is to be performed by the control unit 50 to be describedlater, input/output data, or an image, a voice or a data signal, whichis subject to signal-processing. In particular, the storage unit 40stores the password for setting of the use restriction input through therear password input unit 20 under the control of the control unit 50.

The control unit 50 controls the overall operations of the portableterminal, and particularly controls the operations for the setting andthe releasing of the use restriction according to the present invention.

In detail, the control unit 50 controls the rear password input unit 20to be in an input standby state if an instruction for setting of the userestriction is input from the user through the user input unit 30. If apassword for setting of the use restriction is input through the rearpassword input unit 20, the control unit 50 stores the password for thesetting of the use restriction into the storage unit 40 and sets the userestriction.

In addition, the control unit 50 controls the rear password input unit20 to be in the input standby state if an instruction for the releasingof the use restriction is input from the user in the state that the userestriction is set, and determines the releasing of the use restrictiondepending on the password for releasing of the use restriction, which isinput through the rear password input unit 20.

In other words, if the password for the releasing of the use restrictionis input through the rear password input unit 20, the control unit 50compares the input releasing password with the setting password storedin the storage unit 40. If the input releasing password is matched tothe setting password, the control unit 50 controls the portable terminalto be available by releasing the use restriction. Otherwise, the controlunit 50 controls the portable terminal not to be available bymaintaining the use restriction.

Meanwhile, description has been made in that the rear password inputunit 20 may be realized using various sections and thus the password forthe use restriction may be variously set through the aboveconfiguration. As the rear password input unit 20 is realized using thetouch sensor among the various sections, when the setting password isformed in a specific form of a letter, a number, a symbol, or a graphic,errors may occur in releasing the use restriction depending ondirectional states of the portable terminal when inputting the password.Accordingly, in order to prevent the errors, additional components maybe provided.

In other words, the user must input the password into the rear passwordinput unit 20 while gripping the portable terminal to face down the rearpassword input unit 20 so that the input action of the password is notexposed to others when the user releases the use restriction for theportable terminal in a space shared with the others. However, the usermay input the password into the rear password input unit 20 whilegripping the overturned portable terminal to face up the rear passwordinput unit 20 since the password may not be exposed to others when theuser releases the use restriction for the portable terminal in a spacewhere the user is left alone.

In this case, the input state of the password into the rear passwordinput unit, which faces down, is defined as a normal input state, andthe input state of the password into the rear password input unit 20,which faces up in the overturn portable terminal, is defined as areverse input state.

When a password is input into the rear password input unit 20 in thereverse input state in order to release the use restriction, andparticularly, the setting password has a specific shape, even if theuser inputs a password having the same shape as that of the password setin the reverse input state, the shape of the password is reversely inputas if the password is reflected in a mirror. Accordingly, the controlunit 50 determines the input password as being mismatched from the setpassword in shape and thus does not release the use restriction, therebycausing errors.

That is to say, if a setting password is stored by inputting a letter of“G” in the normal input state as illustrated in FIG. 7A, the storedsetting password is reversed as illustrated in FIG. 7B when viewed fromthe rear surface of the portable terminal. Accordingly, if the useridentically inputs the latter of “G” into the rear password input unit20 in the reverse input state, the control unit 50 determines the storedsetting password as being mismatched from the input releasing password.

Therefore, in order to prevent the errors in releasing the userestriction, the portable terminal may further include a directionsensing unit 60, and the control unit 50 may be configured to include aninput state determining unit 51 and a password transforming unit 52 asillustrated in FIG. 2.

The direction sensing unit 60 senses a direction that the rear passwordinput unit 20 faces, that is, senses whether the rear password inputunit 20 faces down or up.

The input state determining unit 51 receives a sensing signal from thedirection sensing unit 60 to determine whether the rear password inputunit 20 is in the normal input state to face down or in the reverseinput state to face up, if the releasing password is input through therear password input unit 20.

If the input state determining unit 51 determines the rear passwordinput unit 20 as being in the reverse input state, the passwordtransforming unit 52 reverses the shape of the input releasing passwordto a shape reflected in a mirror.

Accordingly, the reversed shape of the releasing password input throughthe password transforming unit 52 becomes the same shape as that of thestored setting password. Because of this, only if the user inputs thesame password, even if a releasing password is input in the reverseinput state, the control unit 50 determines the input releasing passwordas being matched to the setting password to release the use restriction.

The configuration of the portable terminal according to the firstembodiment has been described, and a method of setting and releasing theuse restriction for the portable terminal having the above configurationwill be described with reference to the flowcharts shown in FIGS. 11 to13 below.

The method of releasing and setting the use restriction for the portableterminal according to the present invention may include a step ofsetting the use restriction (S100) and a step of releasing the set userestriction (S200).

First, the step of setting the use restriction (S100) will be describedwith reference to the flowchart shown in FIG. 11.

The control unit 50 controls the rear password input unit 20 to be in aninput standby state (S120) so that the setting password may be input ifan instruction for the setting of the use restriction is input from theuser (S110).

In this case, the control unit 50 may further perform a step (S130) ofreceiving from the user the selection of whether or not to display thesetting password, which is to be input in the subsequent step ofinputting the setting password, on the display unit 10, by displaying aselection menu on the display unit 10 so that the user may selectwhether or not to display the setting password input through the rearpassword input unit 20 on the display unit 10.

Then, the rear password input unit 20 receives the setting password fromthe user (S140).

In this case, the input setting password may be one of a specific shape,a directional pattern, a sequential pattern, a signal pattern, and anoperating pattern depending on sections used to realize the rearpassword input unit 20. Since the sections used to realize the rearpassword input unit 20 and the type of the setting password have beendescribed above in detail in the configuration of the portable terminal,the details thereof will be omitted below in order to avoid redundancy.

If the setting password is input, the control unit 50 may display ascreen image of “Please input the password once more” on the displayunit 10, and the rear password input unit 20 may receive the settingpassword from the user again (S150).

In this case, if the user selects that the setting password is displayedon the display unit 10, and inputs, for example, the letter of “G” inputinto the rear password input unit 20, the control unit 50 may display ascreen image of “G is right?” on the display unit 10 to determine if theuser correctly recognizes the input setting password.

In this case, it is preferred that the process of displaying the settingpassword on the display unit 10 in order to check the input settingpassword is performed only when the user sets the use restriction in aspace where the user is left alone because the setting password may leakin a space with others around the user.

If the same setting password is input once more, the control unit 50determines if the input setting password is matched to the settingpassword which is input once more (S160).

If the setting password, which is input first, is mismatched from thesetting password, which is input once more, according to thedetermination result, an error message of “passwords are mismatched fromeach other is displayed and the procedure is returned to step S140 orS150. If two setting passwords are determined as being matched to eachother, the corresponding setting password is stored in the storage unit40 (S170).

The step (S100) of setting the use restriction is completed through theabove steps.

If the use restriction has been set through the setting step (S100), theportable terminal executes a use restriction function afterpredetermined time has elapsed without an external operation or anexternal input. In order for a user to use the portable terminal underthe execution of the use restriction function, the use restrictionfunction must be released. Accordingly, hereinafter, the step ofreleasing the use restriction (S200) will be described with reference toFIG. 12.

If the instruction for the releasing of the use restriction is inputfrom the user under the execution of the use restriction (S210), thecontrol unit 50 controls the rear password input unit 20 to be in theinput standby state so that the releasing password may be input (S220).

Then, the rear password input unit 20 receives the releasing passwordfrom the user (S230).

If the releasing password is input, the control unit 50 compares theinput releasing password with the setting password stored in the storageunit 40 to determine if the input releasing password is matched to thestored setting password (S240).

If the input releasing password is mismatched from the stored settingpassword according to the determination result, the control unit 50performs a control operation so that the use restriction is maintainedwithout change and displays the error message of “passwords aremismatched to each other” on the display unit 10 while requesting theuser to input the releasing password again.

In addition, if the input releasing password is matched to the storedsetting password according to the determination result, the control unit50 immediately releases the use restriction in progress (S250).

The releasing step (S200) is completed through the above steps.

Meanwhile, the control unit 50 may perform steps illustrated in FIG. 13before determining the releasing of the use restriction by comparing theinput releasing password with the setting password, when the rearpassword input unit 20 is realized using the touch sensor and thesetting password has a specific shape, in step S240 of determining thereleasing the use restriction.

First, the control unit 50 receives the signal related to the facingdirection of the rear password input unit 20 from the directing sensingunit 60 (S241).

Thereafter, the control unit 50 determines depending on the sensingsignal from the directing sensing unit 60 whether the releasing passwordis input in the normal input state that the rear password input unit 20faces down, or in the reverse input state that the rear password inputunit 20 faces up (S242).

If determining the releasing password as being input in the normal inputstate, the control unit 50 compares the input releasing password withthe setting password stored without change to determine whether torelease the use restriction (S240).

On the contrast, if determining the input releasing password as beinginput in the reverse input state, the control unit 50 reverses the inputreleasing password to have the shape reflected in a mirror (S243).

Then, the control unit 50 determines whether or not to release the userestriction by comparing the releasing password having the reversedshape with the stored setting password (S240).

FIG. 14 is a block diagram illustrating a portable terminal according toa second embodiment of the present invention which has the sameconfiguration as that of the first embodiment described above exceptthat that the directing sensing unit 60 is not included and the controlunit 50 is configured to release the use restriction if the releasingpassword is matched to or symmetrical to the setting password aftercomparing the releasing password with the stored setting password.Accordingly, the following description will be made while focusing onthe difference between the first and second embodiments.

The control unit 50 according to the present embodiment may include anidentity determining unit 53, a symmetry determining unit 54, and arelease determining unit 55 as illustrated in FIG. 15.

If the releasing password is input to release the use restriction, theidentity determining unit 53 compares the input releasing password withthe setting password stored in the storage unit 40 to determine theidentity between two passwords.

The symmetry determining unit 54 compares the input releasing passwordwith the setting password stored in the storage unit 40 to determine thesymmetry between two passwords.

The release determining unit 55 releases the use restriction if theidentity determining unit 53 determines the releasing password as beingmatched to the setting password. If the identity determining unit 53determines the releasing password as being different from the settingpassword, and if the symmetry determining unit 54 determines thereleasing password as being symmetrical to the setting password, therelease determining unit 55 releases the use restriction.

In other words, the control unit 50 is characterized with theconfiguration to release the use restriction when the releasing passwordand the setting password are not only matched to each other, but alsosymmetrical to each other, instead of the configuration to release theuse restriction only when the input releasing password is matched to thestored setting password.

Accordingly, the user may input a password by changing the direction ofthe rear password input unit 20 according to use environments, whenattempting to set or release the use restriction by inputting thesetting password or the releasing password into the rear password inputunit 20. In the case of inputting the password by changing the directionof the rear password input unit 20, if only the identity between thepasswords is determined, errors may occur in releasing the userestriction. Therefore, the errors, which may occur in releasing the userestriction, can be prevented, so that the use restriction function canbe smoothly performed.

In addition, although the user inputs the password into the rearpassword input unit 20 while gripping the portable terminal normally(that is, while facing the display unit 10 provided on the front surfaceof the portable terminal) as illustrated in FIG. 5, the user may inputthe password into the rear password input unit 20 while gripping theoverturned portable terminal (that is, while facing the rear passwordinput unit 20 on the rear surface of the portable terminal) when settingor releasing the use restriction in the space where the user is left allalone, which may not be exposed to others

Therefore, according to the use environment, the user may input thesetting password into the rear password input unit 20 while gripping theportable terminal normally to execute the use restriction and then inputthe releasing password into the rear password input unit 20 whilegripping the overturned portable terminal. On the contrast, the user mayinput the setting password into the rear password input unit 20 whilegripping the overturned portable terminal to execute the userestriction, and then input the releasing password into the rearpassword input unit 20 while gripping the portable terminal normally. Inother words, the setting password and the releasing password may beinput into the rear password input unit 20 in mutually differentdirections. In these cases, even though the user inputs the settingpassword and the releasing password matched to each other into the rearpassword input unit 20, both of the setting password and the releasingpassword become symmetrical to each other. Accordingly, if the controlunit 50 determines only the identity between the setting password andthe releasing password, the control unit 50 may determine the settingpassword as being different from the releasing password so that the userestriction may not be released.

For example, when the letter of “G” is input into the rear passwordinput unit 20 in the normally gripping state of the portable terminal,the setting password is stored, and the use restriction function isexecuted as illustrated in FIG. 7A, the stored setting password isrepresented in a symmetrical shape thereto as illustrated in FIG. 7Bwhen viewed from the rear surface. Accordingly, even if the user inputsthe letter of “G” into the rear password input unit 20 as the releasingpassword matched to the setting password while gripping the overturnedportable terminal, the releasing password is represented as beingsymmetrical to the setting code input when the portable terminal isgripped normally. Therefore, the control unit 50 is configured todetermine the identify and the symmetry between two passcodes throughthe identity determining unit 53 and the symmetry determining unit 54,respectively, and to release the use restriction through the releasedetermining unit 55 if the passwords are determined as being matched toeach other, or if the passwords are determined as being symmetrical toeach other and not matched to each other, thereby preventing the errors.

In this case, in the following description, regarding a direction ofinputting the setting password or the releasing password for the userestriction into the rear password input unit 20, an input directionwhen the user grips the portable terminal normally to face the displayunit 10 on the front surface of the portable terminal is defined as aforward direction, and an input direction when the user overturns andgrips the portable terminal to face the rear password input unit 20 isdefined as a reverse direction.

As described above, the configuration of the portable terminal accordingto the second embodiment of the present invention has been described.Hereinafter, a method of setting and releasing the use restriction forthe portable terminal having the above configuration will be describedwith reference to FIGS. 16 and 17.

The method of setting and releasing the use restriction may be mainlyclassified into steps of setting the use restriction (S310) and ofreleasing the use restriction that has been set (S320). First, the stepof setting the use restriction (S310) will be described below withreference to the flowchart illustrated in FIG. 16.

If the instruction for the setting of the use restriction is input fromthe user (S311), the control unit 50 controls the rear password inputunit 20 to be in the input standby state so that the setting passwordmay be input (S312).

Then, the rear password input unit 20 receives the setting password fromthe user (S313).

In the step of inputting the setting password (S313), setting passwordsmay be received from the user twice in order to prevent an input error.Only if the setting passwords, which are input twice, are matched toeach other, the control unit 50 may determine that the setting passwordis correctly input and control the procedure to the next step.

If the setting password is correctly input into the rear password inputunit 20 in step S313, the control unit stores the corresponding settingpassword into the storage unit 40 (S314) and executes the userestriction function of the portable terminal (S315). Through the abovesteps, the step of setting the use restriction is completed (S310).

Next, the step of releasing the use restriction (S320) will be describedbelow with reference to the flowchart illustrated in FIG. 17. If theinstruction for the releasing of the use restriction is input from theuser under the execution of the use restriction function (S321), thecontrol unit 50 controls the rear password input unit 20 to be in theinput standby state so that the releasing password may be input (S322).

Then, the rear password input unit 20 receives the releasing passwordfrom the user (S323).

If the releasing password is input, the control unit 50 compares theinput releasing password with the setting password stored in the storageunit 40. Accordingly, if the two passwords are matched to each other orsymmetrical to each other, the use restriction function may be released.In detail, the identity between two passwords is primarily determined bycomparing the input releasing password with the stored setting password(S324).

If the two passwords are matched to each other according to thedetermination result in step S324, step S326 is performed. If the twopasswords are different from each other, the symmetry between the twopasswords is secondarily determined by comparing the input releasingpassword with the stored setting password (S325).

In addition, the use restriction is released according to thedetermination results in steps S324 and S325 (S326). In other words, ifthe two passwords are determined as being matched to each otheraccording to the determination result in the step S324, the userestriction may be released. If the two passwords are determined asbeing different from each other and symmetrical to each other accordingto the determination result in the step S325, the use restriction may bereleased. Through the above steps, the step of releasing the userestriction (S320) is completed.

If the two passwords are determined as being neither matched to norsymmetrical to each other according to the determination results in thesteps S324 and S325, the control unit 50 performs a control operation tokeep on executing the use restriction while displaying an error messageof “the passwords are mismatched from each other” on the display unit 10to request the user to input the releasing password again.

FIG. 18 is a block diagram illustrating a portable terminal according tothe third embodiment of the present invention, which has the sameconfiguration as that of the second embodiment except that the settingpassword or the releasing password for the use restriction is input intothe display unit 10 as well as the rear password input unit 20.

That is to say, in the present embodiment, according to useenvironments, the user may input a password into the rear password inputunit 20 in the forward direction in a place shared with others toprevent the password from being exposed. In addition, under anenvironment that the password may not be exposed to others, the user mayinput the password into the display unit 10 as well as the rear passwordinput unit 20 to set or release the use restriction according to theconveniences of the user.

In this case, when the password input into the display unit 10 iscompared with the password input into the rear password input unit 20,the password input into the display unit 10 is matched to a passwordinput in the reverse direction, and symmetrical to a password input inthe forward direction.

Accordingly, when the passwords are not only input into the rearpassword input unit 20 in different directions, but also input intomutually different input sections in setting and releasing the userestriction, that is, when the setting password is input into thedisplay unit 10 and the releasing password is input into the rearpassword input unit 20, or vice versa, the control unit 500 releases theuse restriction when the setting password is matched to or symmetricalto the releasing password, thereby preventing errors, similarly to thesecond embodiment.

FIGS. 19 and 20 are flowcharts illustrating a method of setting andreleasing the use restriction for a portable terminal according to thethird embodiment, and the following description will be made whilefocusing on the difference from the method of setting and releasing theuse restriction according to the second embodiment described above.

First, as illustrated in FIG. 19, in a step of setting the userestriction (S410), if an instruction for the setting of the userestriction is input from the user (S411), the control unit 50 controlsthe display unit 10 and the rear password input unit 20 to be in theinput standby state so that the setting password may be input (S412).

Then, any one of the display unit 10 and the rear password input unit 20selected by the user receives the setting password from the user (S413).

In other words, although inputting the setting password by selecting therear password input unit 20 under a use environment that the settingpassword may be exposed to others, the user may input the settingpassword by randomly selecting any one of the display unit 10 and therear password input unit 20 according to the convenience of the userunder a use environment that the setting password may not be exposed toothers at all.

If the setting password is input into any one of the display unit 10 andthe rear password input unit 20 selected by the user in step S413, thecontrol unit 50 stores the setting password in the storage unit 40(S414) and executes the use restriction function of the portableterminal (S415).

Next, in the step of releasing the use restriction (S420) as illustratedin FIG. 20, if the instruction for the releasing of the use restrictionis input from the user under the execution of the use restrictionfunction (S421), the control unit 50 controls the display unit 10 andthe rear password input unit 20 to be in the input standby state so thatthe releasing password may be input (S422).

Then, any one of the display unit 10 and the rear password input unit 20selected by the user receives the releasing password from the user(S423).

In other words, the user may input the releasing password by randomlyselecting any one of the display unit and the rear password input unit20 according to use environments and conveniences of the user, similarlyto the case of inputting the setting passwords.

If the releasing password is input into any one of the display unit 10and the rear password input unit 20 selected by the user, the identitybetween two passwords is primarily determined by comparing the inputreleasing password with the stored setting password (S424) and thesymmetry between the two passwords is secondarily determined if the twopasswords are different from each other (S425).

Subsequently, if the two passwords are determined as being matched toeach other according to the determination result in the step S424, theuse restriction may be released, and, if the two passwords aredetermined as being different from each other and symmetrical to eachother according to the determination result in the step S425, the userestriction may be released (S426).

FIG. 21 is a block diagram illustrating a portable terminal according tothe fourth embodiment of the present invention, which has the sameconfiguration as that of the second embodiment described above exceptthat an input direction selection unit 70 is further included, and thecontrol unit 50 is configured to determine the releasing of the userestriction depending on input directions. Accordingly, the followingdescription will be made while focusing on the difference from thesecond embodiment.

The portable terminal according to the fourth embodiment of the presentinvention further includes the input direction selection unit 70.

The input direction selection unit 70 receives from the user theselection of whether the setting password or the releasing password isto be input in the forward direction or the reverse direction before theuser inputs the setting password or the releasing password into the rearpassword input unit 20.

To this end, if the setting password or the releasing password is input,the input direction selection unit 70 displays a selection menu for aninput direction on the display unit 10 so that the user may select theinput direction, and receives from the user the selection of the forwarddirection or the reverse direction.

Then, if the user inputs the setting password into the rear passwordinput unit 20 in the selected input direction after selecting the inputdirection in the setting of the use restriction, the control unit 50stores the input setting password and the selected input direction inthe storage unit 40 while executing the use restriction.

In addition, if the user inputs the releasing password into the rearpassword input unit 20 in the selected input direction after selectingthe input direction in the releasing of the use restriction, the controlunit 50 determines the releasing of the use restriction by comparingboth of the input releasing password and the selected input directionwith the stored setting password and the input directions in the settingof the use restriction, respectively.

To this end, the control unit 50 may further include an input directiondetermining unit 56, the identity determining unit 53, the symmetrydetermining unit 54, and the release determining unit 55.

The input direction determining unit 56 compares the input direction inthe setting of the use restriction, which is stored in the storage unit40, with the input direction selected in the releasing of the userestriction to determine if two input directions are identical to eachother.

The identity determining unit 53 compares the releasing password inputin the releasing of the use restriction with the setting password storedin the storage unit 40 to determine the identity between two passwords.

The symmetry determining unit 54 compares the releasing password inputin the releasing of the use restriction with the stored setting passwordto determine the symmetry between two passwords.

The release determining unit 55 releases the use restriction if theidentity determining unit 53 determines the releasing password as beingmatched to the setting password, on the assumption that the inputdirection determining unit 56 determines the two input directions asbeing identical to each other, that is, that both of the inputdirections in the setting and the releasing of the use restriction areidentical to each other as the forward direction or the reversedirection.

In addition, the release determining unit 55 releases the userestriction if the symmetry determining unit 54 determines the releasingpassword as being symmetrical to the setting password, on the assumptionthat the input direction determining unit 56 determines the two inputdirections as being different from each other, that is, on theassumption that the direction in the setting of the use restriction isthe forward direction but the direction in the releasing of the userestriction is the reverse direction, or the direction in the setting ofthe use restriction is the reverse direction, but the direction in thereleasing of the use restriction is the forward direction.

FIGS. 22 and 23 are flowcharts illustrating a method of setting andreleasing use restriction for the portable terminal according to thefourth embodiment. The following description will be made while focusingon the difference from the method of setting and releasing the userestriction according to the second embodiment.

First, as illustrated in FIG. 22, in a step of setting the userestriction (S510), if an instruction for the setting of the userestriction is input from the user (S511), the input direction selectionunit 70 receives from the user the selection of whether the settingpassword is to be input in the forward direction or the reversedirection after displaying the selection menu for the input direction ofthe rear password input unit 20 on the display unit 10 (S512).

In other words, although the user must select the forward direction toprevent the password from being exposed under the situation that mayexpose the password, the user may freely select the forward direction orthe reverse direction according to the conveniences of the user underthe situation that may not expose the password.

If the input direction is selected from the user, the control unit 50controls the rear password input unit 20 to be in the input standbystate so that the setting password may be input (S513), and the rearpassword input unit 20 receives the setting password from the user(S514).

In this case, the user inputs the setting password into the rearpassword input unit 20 according to the input direction selected by theuser. That is to say, the user inputs the setting password into the rearpassword input unit 20 while gripping the portable terminal normally ifselecting the forward direction, but inputs the setting password intothe rear password input unit 20 while gripping the overturned portableterminal if selecting the reverse direction.

Then, if the setting password is input into the rear password input unit20 in the selected input direction, the control unit 50 stores the inputsetting password and the selected input direction (that is, the forwarddirection or the reverse direction) into the storage unit 40 (S515) andexecutes the use restriction function of the portable terminal (S516).

Next, in the step of releasing the use restriction (S520) as illustratedin FIG. 23, if the instruction for the releasing of the use restrictionis input from the user (S521), the input direction selection unit 70receives from the user the selection of an input direction that thereleasing password is to be input after displaying the selection menufor the input direction of the rear password input unit 20 on thedisplay unit 10 (S522).

Then, if the input direction of the releasing password is selected bythe user, the control unit 50 controls the rear password input unit 20to be in the input standby state so that the releasing password may beinput (S523), and the rear password input unit 20 receives the releasingpassword from the user (S524).

Similarly, it is natural that the user should input the releasingpassword while gripping the portable terminal corresponding to the inputdirection selected by the user.

If the releasing password is input into the rear password input unit 20in the selected input direction, the control unit 50 compares the inputdirection selected in the releasing of the use restriction with thestored input direction in the setting of the use restriction todetermine the identity between two input directions (S525).

Then, if the two input directions are determined as being identical toeach other according to the determination result in step S525, it isdetermined if the input releasing password and the stored settingpassword are matched to each other (S526). If the two input directionsare determined as being different from each other, it is determined ifthe input releasing password and the stored setting password aresymmetrical to each other (S527).

Then, if the releasing password and the setting password are determinedas being matched to each other in step S526, or symmetrical to eachother in step S527, the use restriction is released (S528).

FIG. 24 is a block diagram illustrating a portable terminal according toa fifth embodiment of the present invention, which has the sameconfiguration as that of the fourth embodiment except that the settingpassword or the releasing password for the use restriction is input intothe display unit 10 as well as the rear password input unit 20.

The portable terminal according to the forth embodiment of the presentinvention further includes an input section selection unit 80. The inputsection selection unit 80 receives from the user the selection of one ofthe display unit 10 and the rear password input unit 20 to input thesetting password or the releasing password.

To this end, the input section selection unit 80 displays a selectionmenu for input sections on the display unit 10 so that the user mayselect the input section if the setting password or the releasingpassword is input, and receives from the user the selection of thedisplay unit 10 or the rear password input unit 20.

In other words, although the user may input the setting password byselecting the rear password input unit 20 as the input section under thesituation that may expose the password, the user may select one of thedisplay unit 10 and the rear password input unit 20 as the input sectionaccording to the conveniences of the user under the situation that maynot expose the password.

In addition, the input direction selection unit 70 receives theselection of the input direction of the rear password input unit 20.Accordingly, different from the fourth embodiment described above, theinput direction selection unit 70 may be configured to be activated onlyif the user selects the rear password input unit 20 as the input sectionthrough the input section selection unit 80.

Further, if the user selects the input section in the setting of the userestriction, selects the input direction, and inputs the settingpassword into the display unit 10 or the rear password input unit 20according to the selected input section and the selected inputdirection, the control unit 50 stores the selected input section (thatis, the display unit 10 or the rear password input unit 20) and theselected input direction (naturally, when the rear password input unit20 is selected as the input section) in the storage unit 40 togetherwith the input setting password while executing the use restriction.

If the user selects the input section and the input direction in thereleasing of the use restriction, and inputs the setting password intothe display unit 10 or the rear password input unit 20 according to theselected input section and the selected input direction, the controlunit compares the input releasing password, and the input section andthe input direction in the releasing of the use restriction with thestored setting password, and the input section and the input directionin the setting of the password to determine the releasing of the userestriction.

To this end, the control unit 50 may further include an input sectiondetermining unit 57, the input direction determining unit 56, theidentity determining unit 53, the symmetry determining unit 54, and therelease determining unit 55.

The input section determining unit 57 compares the input section in thesetting of the use restriction, which is stored in the storage unit 40,with the input section selected in the releasing of the use restrictionto determine if two input section are identical to each other, and todetermine whether the selected input section is the display unit 10 orthe rear password input unit 20.

If the rear password input unit 20 is selected as the input section, theinput direction determining unit 56 compares the input direction in thesetting of the use restriction, which is stored in the storage unit 40,with the input direction selected in the releasing of the userestriction to determine if the two input directions are identical toeach other, and to determine an input direction selected from both ofthe forward direction and the reverse direction.

The identity determining unit 53 and the symmetry determining unit 54determine the identity and the symmetry between two passwords,respectively, in the same manners as those of the above embodiments.

The release determining unit 55 releases the use restriction accordingto the determination results in the input section determining unit 57,the input direction determining unit 56, the identity determining unit53, and the symmetry determining unit 54.

In detail, the release determining unit 55 releases the use restrictionif the releasing password and the setting password are determined asbeing matched to each other by the identity determining unit 53 in thefirst case that both of two input sections in the releasing and settingof the use restriction are determined as being identical to each otheras the display unit 10 by the input section determining unit 57, thesecond case that two input directions of the rear password input unit 20in the releasing and the setting of the use restriction are determinedas being identical to each other by the input direction determining unit56 on the assumption that both of two input sections in the releasingand the setting of the use restriction are determined as being identicalto each other as the rear password input unit 20 by the input sectiondetermining unit 57, and the third case that the input direction of therear password input unit 20 is determined as being the reverse directionby the input direction determining unit 56 on the assumption that thetwo input sections in the releasing and the setting of the userestriction are determined as being different from each other by theinput section determining unit 57.

In addition, the release determining unit 55 releases the userestriction if the releasing password and the setting password aredetermined as being symmetrical to each other by the symmetrydetermining unit 54 in the first case that two input directions of therear password input unit 20 in the releasing and the setting of the userestriction are determined as being different from each other by theinput direction determining unit 56 on the assumption that both of twoinput sections in the releasing and the setting of the use restrictionare determined as being identical to each other as the rear passwordinput unit 20 by the input section determining unit 57, and the secondcase that the input direction of the rear password input unit 20 isdetermined as being the forward direction by the input directiondetermining unit 56 on the assumption that the two input sections in thereleasing and the setting of the use restriction are determined as beingdifferent from each other by the input section determining unit 57.

FIGS. 25 and 26 are flowcharts illustrating a method of setting andreleasing the use restriction for the portable terminal according to thefifth embodiment.

First, as illustrated in FIG. 25, in a step of setting the userestriction (S610), if an instruction for the setting of the userestriction is input from the user (S611), the input section selectingunit 80 receives the selection of an input section from the user afterdisplaying the selection menu for the input section on the display unit10 so that the user may select the display unit 10 or the rear passwordinput unit 20 as the input section (S612).

If the display unit 10 is selected as the input section in step S612,the control unit 50 controls the display unit 10 to be in the inputstandby state (S613).

In addition, if the rear password input unit 20 is selected as the inputsection, the control unit 50 operates the input direction selection unit70 to receive from the user the selection of the input direction of therear password input unit 20 (S614) and then controls the rear passwordinput unit 20 to be in the input standby state (S615).

In other words, although the user must select the rear password inputunit 20 as the input section and the forward direction as the inputdirection to prevent the password from being exposed under the situationthat may expose the password according to the use environments, the usermay select the display unit 10 or the rear password input unit 20 whileselecting the reverse direction as the input direction according to theconveniences of the user under the situation that may not expose thepassword.

If the input section and the input direction are selected as describedabove, the display unit 10 or the rear password input unit 20 selectedby the user receives the setting password from the user (S616).

Then, if the setting password is input according to the selected inputsection and the input direction, the control unit 50 stores the inputsetting password, the selected input section (that is, the display unit10 or the rear password input unit 20), and the selected input direction(that is, the forward direction or the reverse direction when the inputsection is the rear password input unit 20) in the storage unit 40(S617) and executes the use restriction function of the portableterminal (S618).

Next, in the step of releasing the use restriction (S620) as illustratedin FIG. 26, if the instruction for the releasing of the use restrictionis input from the user (S621), the input section selection unit 80receives from the user the selection of an input section of thereleasing password after displaying the selection menu for the inputsection on the display unit 10 (S622).

If the display unit 10 is selected as the input section in step S622,the control unit 50 controls the display unit 10 to be in the inputstandby state (S623), and, if the rear password input unit 20 isselected as the input section in step S622, the control unit 50 operatesthe input direction selection unit 70 to receive from the user theselection of the input direction of the rear password input unit 20 andthen controls the rear password input unit 20 to be in the input standbystate (S625).

Next, if the input section and the input directions are selected asdescribed above, the display unit 10 or the rear password input unit 20selected by the user receives the releasing password from the user(S626).

Subsequently, if the releasing password is input as described, thecontrol unit 50 determines if the input section selected in thereleasing of the use restriction is identical to the input sectionselected in the setting of the use restriction (S627).

Then, if two input sections are determined as being identical to eachother according to the determination result in step S627, it isdetermined if the two input sections identical to each other correspondto the display unit 10 or the rear password input unit 20 (S628).

In addition, if the two input sections identical to each othercorrespond to the rear password input unit 20 according to thedetermination result in step S628, it is determined if the inputdirection selected in the releasing of the use restriction and thestored input direction in the setting of the use restriction areidentical to each other (S629)

Meanwhile, if the two input sections are determined as being differentfrom each other according to the determination result in step S627, itis determined whether the input direction in the setting or thereleasing of the use restriction with respect to the rear password inputunit of both input sections is the forward direction or the reversedirection (S630).

Then, it is determined if the input releasing password and the storedsetting password are matched to each other (S631) based on thedeterminations in the above steps, in detail, on the assumption that thetwo identical input sections are determined as corresponding to thedisplay unit 10 according to the determination result in step S628, thatthe two input directions in the releasing and the setting of the userestriction are determined as being identical to each other according tothe determination result in step S629, and that the input direction ofthe rear password input unit 20 is determined as being the reversedirection according to the determination result in step S630.

In addition, it is determined if the input releasing password and thestored setting password are symmetrical to each other (S632) on theassumption that the two input directions in the releasing and thesetting of the use restriction are determined as being different fromeach other according to the determination result in step S629 and thatthe input direction of the rear password input unit 20 is determined asbeing the reverse direction according to the determination result instep S630.

The use restriction is released (S633) if the releasing password and thesetting password are determined as being matched to each other accordingto the determination result in step S631, or if the releasing passwordand the setting password are determined as being symmetrical to eachother according to the determination result in step S632.

FIG. 27 is a block diagram illustrating a portable terminal according tothe sixth embodiment of the present invention, which has the sameconfiguration as that of the second embodiment described above exceptthat a face recognizing unit 90 is further included, and the controlunit 50 is configured to variously determine the releasing of the userestriction depending on face recognition states.

The portable terminal according to the present sixth embodiment furtherincludes the face recognizing unit 90, and the face recognizing unit 90recognizes the facial contour of the user through an entire surface of abody of the portable terminal when the setting password or the releasingpassword is input into the rear password input unit 20 to createinformation on the face recognition states.

Since the technologies to realize the functions of the face recognizingunit 90 are disclosed in various prior arts including Korean PatentRegistration Nos. 10-1000130 and 10-0901125, well known in the art, towhich the invention pertains, and variously applied to typical portableterminals, the details thereof will be omitted below.

In this case, the recognition information of the face recognizing unit90 is related to the input direction of the rear password input unit 20.In other words, the face of the user is recognized when the settingpassword or the releasing password is input into the rear password inputunit 20, which refers to that the setting password or the releasingpassword is input in the forward direction. On the contrast, the face ofthe user is not recognized when the setting password or the releasingpassword is input into the rear password input unit 20, which refers tothat the setting password or the releasing password is input in thereverse direction.

In addition, if the setting password is into the rear password inputunit 20, the control unit 50 stores the input setting password and therecognition information on the face recognition states, which is createdby the face recognizing unit 90, in the storage unit 40 to execute theuse restriction.

In addition, if the releasing password is input into the rear passwordinput unit 20 in the releasing of the use restriction, the control unit50 compares the input releasing password, and the recognitioninformation on the face recognition states, which is created by the facerecognizing unit 90 in the releasing of the use restriction, with thestored setting password and the recognition information when the settingpassword is input, respectively, to determine the releasing of the userestriction.

To this end, the control unit 50 further includes a recognitioninformation determining unit 58, the identity determining unit 53, thesymmetry determining unit 54, and the release determining unit 55.

The recognition information determining unit 58 compares the recognitioninformation in the setting of the use restriction, which is stored inthe storage unit 40, with the recognition information in the releasingof the use restriction to determine if two pieces of recognitioninformation are matched to each other.

The identity determining unit 53 and the symmetry determining unit 54compare the stored setting password with the releasing password input inthe releasing of the use restriction to determine the identity and thesymmetry between two passwords, respectively.

The release determining unit 55 releases the use restriction if thereleasing password and the setting password are determined as beingmatched to each other by the identity determine unit 53 on theassumption that two pieces of recognition information are determined asbeing matched to each other by the recognition information determiningunit 58, that is, both pieces of the recognition information created inthe setting and the releasing of the use restriction are determined asbeing face recognition information obtained by recognizing the face ofthe user or non-recognition information.

In addition, the release determining unit 55 releases the userestriction if the releasing password and the setting password aredetermined as being symmetrical to each other by the symmetrydetermining unit 54 on the assumption that the two pieces of recognitioninformation are determined as being different from each other by therecognition information determining unit 58, that is, on the assumptionthat the face recognition information is created in the setting of theuse restriction, and non-recognition information is created in thereleasing of the use restriction, or the non-recognition information iscreated in the setting of the use restriction, and the face recognitioninformation is created in the releasing of the use restriction.

FIGS. 28 and 29 are flowcharts illustrating a method of setting andreleasing the use restriction for the portable terminal according to thesixth embodiment.

First, as illustrated in FIG. 28, in a step of setting the userestriction (S710), if an instruction for the setting of the userestriction is input from the user (S711), the control unit 50 controlsthe rear password input unit 20 to be in the input standby state (S712),and the rear password input unit 20 receives the setting password fromthe user (S713).

Then, when the setting password is input as described above, the facerecognizing unit 90 creates the recognition information on the facerecognition states of the user under the control of the control unit 50(S714).

In this case, the created recognition information becomes facerecognition information obtained by recognizing the face if the userinputs the setting password in the forward direction, but anon-recognition information of the face if the user inputs the settingpassword in the reverse direction.

If the setting password is input into the rear password input unit 20 asdescribed above, the control unit 50 stores the input setting passwordand the recognition information created in the setting of the userestriction into the storage unit 40 (S715) and executes the userestriction function of the portable terminal (S716).

Next, in the step of releasing the use restriction (S720) as illustratedin FIG. 29, if the instruction for the releasing of the use restrictionis input from the user (S721), the control unit 50 controls the rearpassword input unit 20 to be in the input standby state (S722), and therear password input unit 20 receives the releasing password from theuser (S723).

Then, when the releasing password is input described above, the facerecognizing unit 90 creates the recognition information on the facerecognition states of the user under the control of the control unit 50(S724).

If the releasing password is input into the rear password input unit 20as described above, the control unit 50 compares the recognitioninformation created in the releasing of the use restriction with thestored recognition information in the setting of the use restriction todetermine if the two pieces of recognition information are matched toeach other (S725).

In addition, if the two pieces of recognition information are determinedas being matched to each other according to the determination result instep S725, it is determined if the input releasing password and thestored setting password are matched to each other (S726). If the twopieces of recognition information are determined as being different fromeach other, it is determined if the input releasing password and thestored setting password are symmetrical to each other (S727).

Further, if the releasing password and the setting password aredetermined as being matched to each other in step S726, or if thereleasing password and the setting password are determined as beingsymmetrical to each other in step S727, the use restriction is released(S728).

FIG. 30 is a block diagram illustrating a portable terminal according toa seventh embodiment of the present invention, which has the sameconfiguration as that of the sixth embodiment except that the settingpassword or the releasing password for the use restriction is input intothe display unit 10 as well as the rear password input unit 20.

The portable terminal according to the seventh embodiment of the presentinvention further includes the input section selection unit 80, and theinput section selection unit 80 receives from the user the selection ofone of the display unit 10 and the rear password input unit 20 to inputthe setting password or the releasing password, similarly to the fifthembodiment.

In addition, the face recognizing unit 90 is a section to determine theinput direction of the rear password input unit 20. Accordingly,different from the sixth embodiment described above, the facerecognizing unit 90 may be configured to be activated only if the userselects the rear password input unit 20 as the input section through theinput section selection unit 80.

In addition, if the user inputs the setting password through theselected input section in the setting of the use restriction, thecontrol unit 50 stores the input setting password, the selected inputsection, and the recognition information created by the face recognizingunit 90 (naturally, when the rear password input unit 20 is selected asthe input section) in the storage unit 40 to execute the userestriction.

In addition, if the user inputs the releasing password into the selectedinput section in the releasing of the use restriction, the control unit50 compares the input releasing password, the input section in thereleasing of the use restriction, and the recognition informationcreated in the releasing of the use restriction with the stored settingpassword, the input section in the setting of the use restriction, andthe recognition information created in the setting of the userestriction, respectively, to determine the releasing of the userestriction.

To this end, the control unit 50 may further include the input sectiondetermining unit 57, the recognition information determining unit 58,the identity determining unit 53, the symmetry determining unit 54, andthe release determining unit 55.

The input section determining unit 57 compares the input section in thesetting of the use restriction, which is stored in the storage unit 40,with the input section selected in the releasing of the use restrictionto determine if two input sections are identical to each other, and todetermine if the selected input section is the display unit 10 or therear password input unit 20.

If the rear password input unit 20 is the input section, the recognitioninformation determining unit 58 compares the recognition information inthe setting of the use restriction, which is stored in the storage unit40, with the recognition information in the releasing of the userestriction to determine if two pieces of recognition information arematched to each other and to determine if the two pieces of recognitioninformation are obtained by recognizing the face of the user.

The identity determining unit 53 and the symmetry determining unit 54determine the identity and the symmetry between two passwords,respectively, similarly the above-described embodiments.

The release determining unit 55 releases the use restriction accordingto the determination results by the input section determining unit 57,the recognition information determining unit 58, the identitydetermining unit 53, and the symmetry determining unit 54.

In detail, the release determining unit 55 releases the use restrictionif the releasing password and the setting password are determined asbeing matched to each other by the identity determining unit 53 in thefirst case that two input sections in the setting and the releasing ofthe use restriction are determined as being identical to each other asthe display unit 10 by the input section determining unit 57, the secondcase that the two input sections in the setting and the releasing of theuse restriction are determined as being identical to each other as therear password input unit 20 by the input section determining unit 57,and the two pieces of recognition information in the setting and thereleasing of the use restriction are determined as being matched to eachother by the recognition information determining unit 58, and the thirdcase that two input sections in the setting and the releasing of the userestriction are determined as being different from each other by theinput section determining unit 57 and the recognition information isdetermined as not being the face recognition information of the user bythe recognition information determining unit 58.

In addition, the release determining unit 55 release the use restrictionif the releasing password and the setting password are determined asbeing symmetrical to each other by the symmetry determining unit 54 inthe first case that the two input sections in the setting and thereleasing of the use restriction are determined as being identical toeach other as the rear password input unit 20 by the input sectiondetermining unit 57 and the two pieces of recognition information in thesetting and the releasing of the use restriction are determined as beingdifferent from each other by the recognition information determiningunit 58, and the second case that the two input sections in the settingand the releasing of the use restriction are determined as beingdifferent from each other by the input section determining unit 57, andthe recognition information is determined as being obtained byrecognizing the face of the user by the recognition informationdetermining unit 58.

FIGS. 31 and 32 are flowcharts illustrating the method of setting andreleasing the use restriction for the portable terminal according to theseventh embodiment.

First, as illustrated in FIG. 31, in a step of setting the userestriction (S810), if an instruction for the setting of the userestriction is input from the user (S811), the input section selectionunit 80 receives the selection of an input section from the user afterdisplaying the selection menu for the input section on the display unit10 so that the user may select the display unit 10 or the rear passwordinput unit 20 as the input section (S812).

As the input section is selected in step S812, the control unit 50controls the display unit 10 or the rear password input unit 20 to be inthe input standby state (S813), and the display unit 10 or the rearpassword input unit 20 selected by the user receives the settingpassword from the user (S814).

In addition, when the setting password is input as described above, ifthe rear password input unit 20 is selected as the input section in stepS812, the face recognizing unit 90 creates the recognition informationon the face recognition states of the user under the control of thecontrol unit 50 (S815).

When the setting password is input as described above, the control unit50 stores the input setting password, the selected input section (thatis, the display unit 10 or the rear password input unit 20), and therecognition information (when the input section is the rear passwordinput unit 20) created by the face recognition unit 90 together in thestorage unit 40 (S816), and executes the use restriction function of theportable terminal (S817).

Next, in the step of releasing the use restriction (S820) as illustratedin FIG. 32, if the instruction for the releasing of the use restrictionis input from the user (S821), the input section selection unit 80receives from the user the selection of an input section of thereleasing password after displaying the selection menu for the inputsection on the display unit 10 (S822).

As the input section is selected in step S822, the control unit 50controls the display unit 10 or the rear password input unit 20 to be inthe input standby state (S823), and the display unit 10 or the rearpassword input unit 20 selected by the user receives the releasingpassword from the user (S824).

Then, when the releasing password is input, if the rear password inputunit 20 is selected as the input section in step S822, the facerecognizing unit 90 creates the recognition information on the facerecognition states of the user under the control of the control unit 50(S825).

If the releasing password is input, the control unit 50 determines ifthe input section selected in the releasing of the use restriction isidentical to the input section in the setting of the use restriction(S826).

In addition, if two input sections are determined as being identical toeach other according to the determination result in step S826, it isdetermined if the two input sections, which are identical to each other,correspond to the display unit 10 or the rear password input unit 20(S827).

Further, if the two identical sections are determined as correspondingto the rear password input unit 20 according to the determination resultin step S827, it is determined if the recognition information created inthe releasing of the use restriction is matched to the storedrecognition information created in the setting of the use restriction(S828).

Meanwhile, if the two input sections are determined as being differentfrom each other according to the determination result in step 826, it isdetermined if the recognition information created in one of cases thatthe setting password is input, or the releasing password is input isobtained by recognizing the face (S829).

Then, it is determined if the input releasing password and the storedsetting password are matched to each other (S830) based on thedeterminations in the above steps, in detail, on the assumption that thetwo input sections identical to each other are determined ascorresponding to the display unit 10 according to the determinationresult in step S827, that the two pieces of recognition information inthe releasing and the setting of the use restriction are determined asbeing matched to each other according to the determination result instep S828, and that the recognition information is determined as notbeing obtained by recognizing the face according to the determinationresult in step S829.

In addition, it is determined if the input releasing password issymmetrical to the stored setting password (S831) on the assumption thatthe two pieces of recognition information in the releasing and thesetting of the use restriction are determined as being different fromeach other according to the determination result in step S828, and thatthe recognition information is determined as being obtained byrecognizing the face according to the determination result in step S829.

Next, the use restriction is released (S832) if the releasing passwordand the setting password are determined as being matched to each otheraccording to the determination result in step S830, or if the releasingpassword and the setting password are determined as being symmetrical toeach other according to the determination result in step S831.

The embodiments of the present invention have been described above. Asdescribed above, according to the present invention, the password in thesetting or the releasing of the use restriction is input into the rearpassword input unit provided on the rear surface of the body of theportable terminal. Accordingly, the rear password input unit which is aninput section is hidden by the body and prevented from being exposed toanother person. Further, even the password input action of the user,such as the touch action of the finger, is hidden by the body and notexposed to other persons, so that the security of the password can beremarkably enhanced. According to use environments having variousprobabilities of exposing the password, the input section and the inputdirection of the password can be freely selected according to theconvenience of the user. In addition, the user can grip the portableterminal in a laying position, or in a laying position on the side ofthe user to use the portable terminal regardless of the input directionof the portable terminal.

What is claimed is:
 1. A portable terminal with a body having a frontsurface and a rear surface, the portable terminal comprising: a displaydevice provided on the front surface; a rear password input deviceprovided on the rear surface to receive a setting password for setting ause restriction for the portable terminal or a releasing password forreleasing the use restriction set for the portable terminal; and acontrol device that stores the setting password in a storage device ifthe setting password is input into the rear password input device whilesetting the use restriction, and that performs comparison of the inputreleasing password with the stored setting password if the releasingpassword is input to release the use restriction if the input releasingpassword is matched to the stored setting password or symmetrical to thestored setting password.
 2. The portable terminal of claim 1, whereinthe control device comprises: an identity determining device thatdetermines if the input releasing password is matched to the storedsetting password; a symmetry determining device that determines if theinput releasing password is symmetrical to the stored setting password;and a release determining device that releases the use restriction ifthe identity determining device determines the input releasing passwordas being matched to the stored setting password, or if the identitydetermining device determines the input releasing password as beingdifferent from the stored setting password, and the symmetry determiningdevice determines the input releasing password as being symmetrical tothe stored setting password.
 3. A portable terminal with a body having afront surface and a rear surface, the portable terminal comprising: adisplay device provided on the front surface; a rear password inputdevice provided on the rear surface to receive a setting password forsetting a use restriction for the portable terminal or a releasingpassword for releasing the use restriction set for the portableterminal; and a control device that stores the setting password in astorage device if the setting password is input into one of the displaydevice and the rear password input device while setting the userestriction, and that performs comparison of the input releasingpassword with the stored setting password if the releasing password isinput to release the use restriction if the input releasing password ismatched to the stored setting password or symmetrical to the storedsetting password.
 4. The portable terminal of claim 3, wherein thecontrol device comprises: an identity determining device that determinesif the input releasing password is matched to the stored settingpassword; a symmetry determining device that determines if the inputreleasing password is symmetrical to the stored setting password; and arelease determining device that releases the use restriction if theidentity determining device determines the input releasing password asbeing matched to the stored setting password, or if the identitydetermining device determines the input releasing password as beingdifferent from the stored setting password, and the symmetry determiningdevice determines the input releasing password as being symmetrical tothe stored setting password.
 5. A method of setting and releasing userestriction for a portable terminal, the method comprising: setting theuse restriction for the portable terminal including a display deviceprovided on a front surface of a body thereof and a rear password inputdevice provided on a rear surface of the body; and releasing the userestriction set for the portable terminal; wherein the setting of theuse restriction comprises: inputting a setting password for the settingof the use restriction into the rear password input device; and storingthe input setting password while setting the use restriction, andwherein the releasing of the use restriction comprises: inputting areleasing password for the releasing of the use restriction into therear password input device; and comparing the input releasing passwordwith the stored setting password to determine the releasing of the userestriction if the input releasing password is matched to the storedsetting password or symmetrical to the stored setting password.
 6. Themethod of claim 5, wherein the determining of the releasing the userestriction comprises: primarily determining if the input releasingpassword is matched to the stored setting password to release the userestriction if the input releasing password is determined as beingmatched to the stored setting password; and secondarily determining ifthe input releasing password is symmetrical to the stored settingpassword if the input releasing password is determined as beingdifferent from the stored setting password in the primarily determining,to release the use restriction if the input releasing password isdetermined as being symmetrical to the stored setting password.
 7. Amethod of setting and releasing use restriction for a portable terminal,the method comprising: setting the use restriction for the portableterminal including a display device provided on a front surface of abody thereof and a rear password input device provided on a rear surfaceof the body; and releasing the use restriction set for the portableterminal, wherein the setting of the use restriction comprises:inputting a setting password for the setting of the use restriction intoone of the display device and the rear password input device; andstoring the input setting password while setting the use restriction,and wherein the releasing of the use restriction comprises: inputting areleasing password for the releasing of the use restriction into one ofthe display device and the rear password input device; and comparing theinput releasing password with the stored setting password to determinethe releasing of the use restriction if the input releasing password ismatched to the stored setting password or symmetrical to the storedsetting password.
 8. The method of claim 7, wherein the determining ofthe releasing the use restriction comprises: primarily determining ifthe input releasing password is matched to the stored setting passwordto release the use restriction if the input releasing password isdetermined as being matched to the stored setting password; andsecondarily determining if the input releasing password is symmetricalto the stored setting password if the input releasing password isdetermined as being different from the stored setting password in theprimarily determining, to release the use restriction if the inputreleasing password is determined as being symmetrical to the storedsetting password.